cover 1917 XU5 to U.S.A. bearing 1915-16 War Charity 5f., 10f. (2), tied by fine strikes of the pictorial "BREMEN 1./T.B./16.1.17./submarine/D.O.R." and pencil crosses, showing manuscript "Tauchbootbrief" adjacent, vertical crease crosses the 5f., scarce and attractive